This makes it possible to use std::thread in single-threaded builds.
All member functions are available, but attempting to create a new
thread will throw an exception.
The main benefit for most targets is that other headers such as <future>
do not need to include the whole of <thread> just to be able to create a
std::thread. That avoids including <stop_token> and std::jthread where
not required.
This also means we can use std::thread::id in <stop_token> instead of
using the gthread wrappers directly.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add new <bits/std_thread.h> header.
* include/Makefile.in: Regenerate.
* include/std/future: Include new header instead of <thread>.
* include/std/stop_token: Include new header instead of
<bits/gthr.h>.
(stop_token::_S_yield()): Use this_thread::yield().
(_Stop_state_t::_M_requester): Change type to std::thread::id.
(_Stop_state_t::_M_request_stop()): Use this_thread::get_id().
(_Stop_state_t::_M_remove_callback(_Stop_cb*)): Likewise.
Use __is_single_threaded() to decide whether to synchronize.
* include/std/thread (thread, operator==, this_thread::get_id)
(this_thread::yield): Move to new header.
(operator<=>, operator!=, operator<, operator<=, operator>)
(operator>=, hash<thread::id>, operator<<): Define even when
gthreads not available.
* src/c++11/thread.cc (_GLIBCXX_NPROCS): Define to 0 when
gthreads not available.
(thread::_State::~_State(), thread::join(), thread::detach())
(thread::_M_start_thread(_State_ptr, void(*)()))
(thread::hardware_concurrency()): Define even when gthreads
not available.
* include/bits/std_thread.h: New file.
(thread, operator==, this_thread::get_id, this_thread::yield):
Define even when gthreads not available.
I'm sending this for consideration, I haven't pushed it.
This removes a number of ugly preprocessor checks for
_GLIBCXX_HAS_GTHREADS because things like std::this_thread::get_id()
and std::this_thread::yield() are always available.
The patch is missing changes to the testsuite to remove some (but
certainly not all) of the { dg-require-gthreads "" } directives. That
hasn't been done yet because it isn't sufficient. The testsuite also
filters out any test with the string "thread" in its path (see
testsuite/libstdc++-dg/conformance.exp) so that needs to be changed if
we want any tests under 30_threads to run for non-gthreads targets.
A follow-up patch could make futures and promises available on targets
with no gthreads support. For example, to use with coroutines. That
needs a little more work, as we'd need a non-gthreads version of
__atomic_futex_unsigned.
Thoughts?
commit 8bd28626e5f9b28192d0e868e922f26d4f40187e
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Wed Nov 11 15:43:03 2020
libstdc++: Enable <thread> without gthreads
This makes it possible to use std::thread in single-threaded builds.
All member functions are available, but attempting to create a new
thread will throw an exception.
The main benefit for most targets is that other headers such as <future>
do not need to include the whole of <thread> just to be able to create a
std::thread. That avoids including <stop_token> and std::jthread where
not required.
This also means we can use std::thread::id in <stop_token> instead of
using the gthread wrappers directly.
libstdc++-v3/ChangeLog:
* include/Makefile.am: Add new <bits/std_thread.h> header.
* include/Makefile.in: Regenerate.
* include/std/future: Include new header instead of <thread>.
* include/std/stop_token: Include new header instead of
<bits/gthr.h>.
(stop_token::_S_yield()): Use this_thread::yield().
(_Stop_state_t::_M_requester): Change type to std::thread::id.
(_Stop_state_t::_M_request_stop()): Use this_thread::get_id().
(_Stop_state_t::_M_remove_callback(_Stop_cb*)): Likewise.
Use __is_single_threaded() to decide whether to synchronize.
* include/std/thread (thread, operator==, this_thread::get_id)
(this_thread::yield): Move to new header.
(operator<=>, operator!=, operator<, operator<=, operator>)
(operator>=, hash<thread::id>, operator<<): Define even when
gthreads not available.
* src/c++11/thread.cc (_GLIBCXX_NPROCS): Define to 0 when
gthreads not available.
(thread::_State::~_State(), thread::join(), thread::detach())
(thread::_M_start_thread(_State_ptr, void(*)()))
(thread::hardware_concurrency()): Define even when gthreads
not available.
* include/bits/std_thread.h: New file.
(thread, operator==, this_thread::get_id, this_thread::yield):
Define even when gthreads not available.
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index 292d89da8ba7..7979f1c589d6 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -187,6 +187,7 @@ bits_headers = \
${bits_srcdir}/std_abs.h \
${bits_srcdir}/std_function.h \
${bits_srcdir}/std_mutex.h \
+ ${bits_srcdir}/std_thread.h \
${bits_srcdir}/stl_algo.h \
${bits_srcdir}/stl_algobase.h \
${bits_srcdir}/stl_bvector.h \
diff --git a/libstdc++-v3/include/bits/std_thread.h
b/libstdc++-v3/include/bits/std_thread.h
new file mode 100644
index 000000000000..41cc942788a1
--- /dev/null
+++ b/libstdc++-v3/include/bits/std_thread.h
@@ -0,0 +1,326 @@
+// std::thread declarations -*- C++ -*-
+
+// Copyright (C) 2008-2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/std_thread.h
+ * This is an internal header file, included by other library headers.
+ * Do not attempt to use it directly. @headername{thread}
+ */
+
+#ifndef _GLIBCXX_THREAD_H
+#define _GLIBCXX_THREAD_H 1
+
+#pragma GCC system_header
+
+#if __cplusplus >= 201103L
+#include <bits/c++config.h>
+
+#include <tuple> // std::tuple
+#include <bits/invoke.h> // std::__invoke
+#include <bits/unique_ptr.h> // std::unique_ptr
+
+#if _GLIBCXX_THREAD_ABI_COMPAT
+#include <bits/shared_ptr.h>
+#endif
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+# include <bits/gthr.h>
+#endif
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ /** @addtogroup threads
+ * @{
+ */
+
+ /// thread
+ class thread
+ {
+ public:
+ // Abstract base class for types that wrap arbitrary functors to be
+ // invoked in the new thread of execution.
+ struct _State
+ {
+ virtual ~_State();
+ virtual void _M_run() = 0;
+ };
+ using _State_ptr = unique_ptr<_State>;
+
+#ifdef _GLIBCXX_HAS_GTHREADS
+ using native_handle_type = __gthread_t;
+#else
+ using native_handle_type = int;
+#endif
+
+ /// thread::id
+ class id
+ {
+ native_handle_type _M_thread;
+
+ public:
+ id() noexcept : _M_thread() { }
+
+ explicit
+ id(native_handle_type __id) : _M_thread(__id) { }
+
+ private:
+ friend class thread;
+ friend struct hash<id>;
+
+ friend bool
+ operator==(id __x, id __y) noexcept;
+
+#if __cpp_lib_three_way_comparison
+ friend strong_ordering
+ operator<=>(id __x, id __y) noexcept;
+#else
+ friend bool
+ operator<(id __x, id __y) noexcept;
+#endif
+
+ template<class _CharT, class _Traits>
+ friend basic_ostream<_CharT, _Traits>&
+ operator<<(basic_ostream<_CharT, _Traits>& __out, id __id);
+ };
+
+ private:
+ id _M_id;
+
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 2097. packaged_task constructors should be constrained
+ // 3039. Unnecessary decay in thread and packaged_task
+ template<typename _Tp>
+ using __not_same = __not_<is_same<__remove_cvref_t<_Tp>, thread>>;
+
+ public:
+ thread() noexcept = default;
+
+ template<typename _Callable, typename... _Args,
+ typename = _Require<__not_same<_Callable>>>
+ explicit
+ thread(_Callable&& __f, _Args&&... __args)
+ {
+ static_assert( __is_invocable<typename decay<_Callable>::type,
+ typename decay<_Args>::type...>::value,
+ "std::thread arguments must be invocable after conversion to rvalues"
+ );
+
+#if defined _GLIBCXX_HAS_GTHREADS && defined GTHR_ACTIVE_PROXY
+ // Create a reference to pthread_create, not just the gthr weak symbol.
+ auto __depend = reinterpret_cast<void(*)()>(&pthread_create);
+#else
+ auto __depend = nullptr;
+#endif
+ using _Wrapper = _Call_wrapper<_Callable, _Args...>;
+ // Create a call wrapper with DECAY_COPY(__f) as its target object
+ // and DECAY_COPY(__args)... as its bound argument entities.
+ _M_start_thread(_State_ptr(new _State_impl<_Wrapper>(
+ std::forward<_Callable>(__f), std::forward<_Args>(__args)...)),
+ __depend);
+ }
+
+ ~thread()
+ {
+ if (joinable())
+ std::terminate();
+ }
+
+ thread(const thread&) = delete;
+
+ thread(thread&& __t) noexcept
+ { swap(__t); }
+
+ thread& operator=(const thread&) = delete;
+
+ thread& operator=(thread&& __t) noexcept
+ {
+ if (joinable())
+ std::terminate();
+ swap(__t);
+ return *this;
+ }
+
+ void
+ swap(thread& __t) noexcept
+ { std::swap(_M_id, __t._M_id); }
+
+ bool
+ joinable() const noexcept
+ { return !(_M_id == id()); }
+
+ void
+ join();
+
+ void
+ detach();
+
+ id
+ get_id() const noexcept
+ { return _M_id; }
+
+ /** @pre thread is joinable
+ */
+ native_handle_type
+ native_handle()
+ { return _M_id._M_thread; }
+
+ // Returns a value that hints at the number of hardware thread contexts.
+ static unsigned int
+ hardware_concurrency() noexcept;
+
+ private:
+ template<typename _Callable>
+ struct _State_impl : public _State
+ {
+ _Callable _M_func;
+
+ template<typename... _Args>
+ _State_impl(_Args&&... __args)
+ : _M_func{{std::forward<_Args>(__args)...}}
+ { }
+
+ void
+ _M_run() { _M_func(); }
+ };
+
+ void
+ _M_start_thread(_State_ptr, void (*)());
+
+#if _GLIBCXX_THREAD_ABI_COMPAT
+ public:
+ struct _Impl_base;
+ typedef shared_ptr<_Impl_base> __shared_base_type;
+ struct _Impl_base
+ {
+ __shared_base_type _M_this_ptr;
+ virtual ~_Impl_base() = default;
+ virtual void _M_run() = 0;
+ };
+
+ private:
+ void
+ _M_start_thread(__shared_base_type, void (*)());
+
+ void
+ _M_start_thread(__shared_base_type);
+#endif
+
+ private:
+ // A call wrapper that does INVOKE(forwarded tuple elements...)
+ template<typename _Tuple>
+ struct _Invoker
+ {
+ _Tuple _M_t;
+
+ template<typename>
+ struct __result;
+ template<typename _Fn, typename... _Args>
+ struct __result<tuple<_Fn, _Args...>>
+ : __invoke_result<_Fn, _Args...>
+ { };
+
+ template<size_t... _Ind>
+ typename __result<_Tuple>::type
+ _M_invoke(_Index_tuple<_Ind...>)
+ { return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
+
+ typename __result<_Tuple>::type
+ operator()()
+ {
+ using _Indices
+ = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
+ return _M_invoke(_Indices());
+ }
+ };
+
+ public:
+ template<typename... _Tp>
+ using _Call_wrapper = _Invoker<tuple<typename decay<_Tp>::type...>>;
+ };
+
+
+ inline void
+ swap(thread& __x, thread& __y) noexcept
+ { __x.swap(__y); }
+
+ inline bool
+ operator==(thread::id __x, thread::id __y) noexcept
+ {
+ // pthread_equal is undefined if either thread ID is not valid, so we
+ // can't safely use __gthread_equal on default-constructed values (nor
+ // the non-zero value returned by this_thread::get_id() for
+ // single-threaded programs using GNU libc). Assume EqualityComparable.
+ return __x._M_thread == __y._M_thread;
+ }
+
+ // N.B. other comparison operators are defined in <thread>
+
+ namespace this_thread
+ {
+ /// this_thread::get_id
+ inline thread::id
+ get_id() noexcept
+ {
+#ifdef _GLIBCXX_HAS_GTHREADS
+
+#ifdef __GLIBC__
+ // For the GNU C library pthread_self() is usable without linking to
+ // libpthread, but prior to version 2.27 the version in libc returns 0,
+ // which breaks the invariant this_thread::get_id() != thread::id{}.
+ //
+ // We know that pthread_t is a scalar type in the GNU C library,
+ // so just use (__gthread_t)1 as the ID of the main (and only) thread.
+ //
+ // This uses __gthread_active_p not __gnu_cxx::__is_single_threaded
+ // because we don't want the thread::id of the main thread to change
+ // if additional threads are created later.
+ if (!__gthread_active_p())
+ return thread::id((__gthread_t)1);
+#endif
+
+ return thread::id(__gthread_self());
+#else
+ return thread::id(1);
+#endif
+ }
+
+ /// this_thread::yield
+ inline void
+ yield() noexcept
+ {
+#if defined _GLIBCXX_HAS_GTHREADS && defined _GLIBCXX_USE_SCHED_YIELD
+ __gthread_yield();
+#endif
+ }
+
+ } // namespace this_thread
+
+ /// @}
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+#endif // C++11
+
+#endif // _GLIBCXX_THREAD_H
diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future
index 5d948018c75c..a3e1ea2c5e40 100644
--- a/libstdc++-v3/include/std/future
+++ b/libstdc++-v3/include/std/future
@@ -36,7 +36,6 @@
#else
#include <mutex> // call_once
-#include <thread>
#include <condition_variable> // __at_thread_exit_elt
#include <system_error>
#include <atomic>
@@ -46,6 +45,7 @@
#include <bits/unique_ptr.h>
#include <bits/shared_ptr.h>
#include <bits/std_function.h>
+#include <bits/std_thread.h>
#include <bits/uses_allocator.h>
#include <ext/aligned_buffer.h>
diff --git a/libstdc++-v3/include/std/stop_token
b/libstdc++-v3/include/std/stop_token
index 7cd01c9713ee..5b2d5a0427c7 100644
--- a/libstdc++-v3/include/std/stop_token
+++ b/libstdc++-v3/include/std/stop_token
@@ -32,15 +32,14 @@
#if __cplusplus > 201703L
#include <atomic>
+#include <bits/std_thread.h>
-#ifdef _GLIBCXX_HAS_GTHREADS
-# define __cpp_lib_jthread 201911L
-# include <bits/gthr.h>
-# if __has_include(<semaphore>)
-# include <semaphore>
-# endif
+#if __has_include(<semaphore>)
+# include <semaphore>
#endif
+#define __cpp_lib_jthread 201911L
+
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -105,9 +104,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
#if defined __i386__ || defined __x86_64__
__builtin_ia32_pause();
-#elif defined _GLIBCXX_HAS_GTHREADS && defined _GLIBCXX_USE_SCHED_YIELD
- __gthread_yield();
#endif
+ this_thread::yield();
}
#ifndef __cpp_lib_semaphore
@@ -162,18 +160,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
std::atomic<value_type> _M_owners{1};
std::atomic<value_type> _M_value{_S_ssrc_counter_inc};
_Stop_cb* _M_head = nullptr;
- struct
- {
-#ifdef _GLIBCXX_HAS_GTHREADS
- __gthread_t _M_id;
- void _M_set() { _M_id = __gthread_self(); }
- bool _M_is_current_thread() const
- { return __gthread_equal(_M_id, __gthread_self()); }
-#else
- void _M_set() { }
- constexpr bool _M_is_current_thread() const { return true; }
-#endif
- } _M_requester;
+ std::thread::id _M_requester;
_Stop_state_t() = default;
@@ -246,7 +233,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
while (!_M_try_lock_and_stop(__old));
- _M_requester._M_set();
+ _M_requester = this_thread::get_id();
while (_M_head)
{
@@ -273,10 +260,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (!__destroyed)
{
__cb->_M_destroyed = nullptr;
-#ifdef _GLIBCXX_HAS_GTHREADS
+
// synchronize with destructor of stop_callback that owns *__cb
- __cb->_M_done.release();
-#endif
+ if (!__gnu_cxx::__is_single_threaded())
+ __cb->_M_done.release();
}
// Avoid relocking if we already know there are no more callbacks.
@@ -353,7 +340,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Despite appearances there is no data race on _M_requester. The only
// write to it happens before the callback is removed from the list,
// and removing it from the list happens before this read.
- if (!_M_requester._M_is_current_thread())
+ if (!(_M_requester == this_thread::get_id()))
{
// Synchronize with completion of callback.
__cb->_M_done.acquire();
diff --git a/libstdc++-v3/include/std/thread b/libstdc++-v3/include/std/thread
index 080036e26097..6ea8a51c0cf8 100644
--- a/libstdc++-v3/include/std/thread
+++ b/libstdc++-v3/include/std/thread
@@ -37,26 +37,18 @@
#include <chrono> // std::chrono::*
-#ifdef _GLIBCXX_USE_NANOSLEEP
-# include <cerrno> // errno, EINTR
-# include <time.h> // nanosleep
-#endif
-
-#if defined(_GLIBCXX_HAS_GTHREADS)
-#include <bits/gthr.h>
-
-#include <memory> // std::unique_ptr
-#include <tuple> // std::tuple
-
#if __cplusplus > 201703L
# include <compare> // std::strong_ordering
# include <stop_token> // std::stop_source, std::stop_token, std::nostopstate
#endif
+#include <bits/std_thread.h> // std::thread, get_id, yield
#include <bits/functional_hash.h> // std::hash
-#include <bits/invoke.h> // std::__invoke
-#endif // _GLIBCXX_HAS_GTHREADS
+#ifdef _GLIBCXX_USE_NANOSLEEP
+# include <cerrno> // errno, EINTR
+# include <time.h> // nanosleep
+#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
@@ -70,221 +62,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @{
*/
-#if defined(_GLIBCXX_HAS_GTHREADS)
- /// thread
- class thread
- {
- public:
- // Abstract base class for types that wrap arbitrary functors to be
- // invoked in the new thread of execution.
- struct _State
- {
- virtual ~_State();
- virtual void _M_run() = 0;
- };
- using _State_ptr = unique_ptr<_State>;
-
- typedef __gthread_t native_handle_type;
-
- /// thread::id
- class id
- {
- native_handle_type _M_thread;
-
- public:
- id() noexcept : _M_thread() { }
-
- explicit
- id(native_handle_type __id) : _M_thread(__id) { }
-
- private:
- friend class thread;
- friend struct hash<id>;
-
- friend bool
- operator==(id __x, id __y) noexcept;
-
-#if __cpp_lib_three_way_comparison
- friend strong_ordering
- operator<=>(id __x, id __y) noexcept;
-#else
- friend bool
- operator<(id __x, id __y) noexcept;
-#endif
-
- template<class _CharT, class _Traits>
- friend basic_ostream<_CharT, _Traits>&
- operator<<(basic_ostream<_CharT, _Traits>& __out, id __id);
- };
-
- private:
- id _M_id;
-
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 2097. packaged_task constructors should be constrained
- // 3039. Unnecessary decay in thread and packaged_task
- template<typename _Tp>
- using __not_same = __not_<is_same<__remove_cvref_t<_Tp>, thread>>;
-
- public:
- thread() noexcept = default;
-
- template<typename _Callable, typename... _Args,
- typename = _Require<__not_same<_Callable>>>
- explicit
- thread(_Callable&& __f, _Args&&... __args)
- {
- static_assert( __is_invocable<typename decay<_Callable>::type,
- typename decay<_Args>::type...>::value,
- "std::thread arguments must be invocable after conversion to rvalues"
- );
-
-#ifdef GTHR_ACTIVE_PROXY
- // Create a reference to pthread_create, not just the gthr weak symbol.
- auto __depend = reinterpret_cast<void(*)()>(&pthread_create);
-#else
- auto __depend = nullptr;
-#endif
- using _Wrapper = _Call_wrapper<_Callable, _Args...>;
- // Create a call wrapper with DECAY_COPY(__f) as its target object
- // and DECAY_COPY(__args)... as its bound argument entities.
- _M_start_thread(_State_ptr(new _State_impl<_Wrapper>(
- std::forward<_Callable>(__f), std::forward<_Args>(__args)...)),
- __depend);
- }
-
- ~thread()
- {
- if (joinable())
- std::terminate();
- }
-
- thread(const thread&) = delete;
-
- thread(thread&& __t) noexcept
- { swap(__t); }
-
- thread& operator=(const thread&) = delete;
-
- thread& operator=(thread&& __t) noexcept
- {
- if (joinable())
- std::terminate();
- swap(__t);
- return *this;
- }
-
- void
- swap(thread& __t) noexcept
- { std::swap(_M_id, __t._M_id); }
-
- bool
- joinable() const noexcept
- { return !(_M_id == id()); }
-
- void
- join();
-
- void
- detach();
-
- id
- get_id() const noexcept
- { return _M_id; }
-
- /** @pre thread is joinable
- */
- native_handle_type
- native_handle()
- { return _M_id._M_thread; }
-
- // Returns a value that hints at the number of hardware thread contexts.
- static unsigned int
- hardware_concurrency() noexcept;
-
- private:
- template<typename _Callable>
- struct _State_impl : public _State
- {
- _Callable _M_func;
-
- template<typename... _Args>
- _State_impl(_Args&&... __args)
- : _M_func{{std::forward<_Args>(__args)...}}
- { }
-
- void
- _M_run() { _M_func(); }
- };
-
- void
- _M_start_thread(_State_ptr, void (*)());
-
-#if _GLIBCXX_THREAD_ABI_COMPAT
- public:
- struct _Impl_base;
- typedef shared_ptr<_Impl_base> __shared_base_type;
- struct _Impl_base
- {
- __shared_base_type _M_this_ptr;
- virtual ~_Impl_base() = default;
- virtual void _M_run() = 0;
- };
-
- private:
- void
- _M_start_thread(__shared_base_type, void (*)());
-
- void
- _M_start_thread(__shared_base_type);
-#endif
-
- private:
- // A call wrapper that does INVOKE(forwarded tuple elements...)
- template<typename _Tuple>
- struct _Invoker
- {
- _Tuple _M_t;
-
- template<typename>
- struct __result;
- template<typename _Fn, typename... _Args>
- struct __result<tuple<_Fn, _Args...>>
- : __invoke_result<_Fn, _Args...>
- { };
-
- template<size_t... _Ind>
- typename __result<_Tuple>::type
- _M_invoke(_Index_tuple<_Ind...>)
- { return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
-
- typename __result<_Tuple>::type
- operator()()
- {
- using _Indices
- = typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
- return _M_invoke(_Indices());
- }
- };
-
- public:
- template<typename... _Tp>
- using _Call_wrapper = _Invoker<tuple<typename decay<_Tp>::type...>>;
- };
-
- inline void
- swap(thread& __x, thread& __y) noexcept
- { __x.swap(__y); }
-
- inline bool
- operator==(thread::id __x, thread::id __y) noexcept
- {
- // pthread_equal is undefined if either thread ID is not valid, so we
- // can't safely use __gthread_equal on default-constructed values (nor
- // the non-zero value returned by this_thread::get_id() for
- // single-threaded programs using GNU libc). Assume EqualityComparable.
- return __x._M_thread == __y._M_thread;
- }
+ // std::thread is defined in <bits/std_thread.h>
#if __cpp_lib_three_way_comparison
inline strong_ordering
@@ -336,7 +114,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
else
return __out << __id._M_thread;
}
-#endif // _GLIBCXX_HAS_GTHREADS
/** @namespace std::this_thread
* @brief ISO C++ 2011 namespace for interacting with the current thread
@@ -345,36 +122,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*/
namespace this_thread
{
-#if defined _GLIBCXX_HAS_GTHREADS
- /// get_id
- inline thread::id
- get_id() noexcept
- {
-#ifdef __GLIBC__
- // For the GNU C library pthread_self() is usable without linking to
- // libpthread.so but returns 0, so we cannot use it in single-threaded
- // programs, because this_thread::get_id() != thread::id{} must be true.
- // We know that pthread_t is an integral type in the GNU C library.
- if (!__gthread_active_p())
- return thread::id(1);
-#endif
- return thread::id(__gthread_self());
- }
-#endif // _GLIBCXX_HAS_GTHREADS
-
- /// yield
- inline void
- yield() noexcept
- {
-#if defined _GLIBCXX_HAS_GTHREADS && defined _GLIBCXX_USE_SCHED_YIELD
- __gthread_yield();
-#endif
- }
-
void
__sleep_for(chrono::seconds, chrono::nanoseconds);
- /// sleep_for
+ /// this_thread::sleep_for
template<typename _Rep, typename _Period>
inline void
sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
@@ -396,7 +147,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif
}
- /// sleep_until
+ /// this_thread::sleep_until
template<typename _Clock, typename _Duration>
inline void
sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
@@ -421,6 +172,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#ifdef __cpp_lib_jthread
+ /// A thread that can be requested to stop and automatically joined.
class jthread
{
public:
diff --git a/libstdc++-v3/src/c++11/thread.cc b/libstdc++-v3/src/c++11/thread.cc
index a4c87d816a58..43c85305c6e6 100644
--- a/libstdc++-v3/src/c++11/thread.cc
+++ b/libstdc++-v3/src/c++11/thread.cc
@@ -40,7 +40,6 @@
#endif
#ifdef _GLIBCXX_HAS_GTHREADS
-
#if defined(_GLIBCXX_USE_GET_NPROCS)
# include <sys/sysinfo.h>
# define _GLIBCXX_NPROCS get_nprocs()
@@ -65,12 +64,16 @@ static inline int get_nprocs()
#elif defined(_GLIBCXX_USE_SC_NPROC_ONLN)
# include <unistd.h>
# define _GLIBCXX_NPROCS sysconf(_SC_NPROC_ONLN)
-#else
+#endif
+#endif // _GLIBCXX_HAS_GTHREADS
+
+#ifndef _GLIBCXX_NPROCS
# define _GLIBCXX_NPROCS 0
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
+#ifdef _GLIBCXX_HAS_GTHREADS
extern "C"
{
static void*
@@ -96,6 +99,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
}
#endif
} // extern "C"
+#endif // _GLIBCXX_HAS_GTHREADS
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -106,8 +110,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
int __e = EINVAL;
+#ifdef _GLIBCXX_HAS_GTHREADS
if (_M_id != id())
__e = __gthread_join(_M_id._M_thread, 0);
+#endif
if (__e)
__throw_system_error(__e);
@@ -120,8 +126,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
int __e = EINVAL;
+#ifdef _GLIBCXX_HAS_GTHREADS
if (_M_id != id())
__e = __gthread_detach(_M_id._M_thread);
+#endif
if (__e)
__throw_system_error(__e);
@@ -132,15 +140,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
thread::_M_start_thread(_State_ptr state, void (*)())
{
+#ifdef _GLIBCXX_HAS_GTHREADS
const int err = __gthread_create(&_M_id._M_thread,
&execute_native_thread_routine,
state.get());
if (err)
__throw_system_error(err);
state.release();
+#else
+ __throw_system_error(EINVAL);
+#endif
}
-#if _GLIBCXX_THREAD_ABI_COMPAT
+#if defined _GLIBCXX_HAS_GTHREADS && _GLIBCXX_THREAD_ABI_COMPAT
void
thread::_M_start_thread(__shared_base_type __b)
{
@@ -169,7 +181,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__throw_system_error(__e);
}
}
-#endif
+#endif // defined _GLIBCXX_HAS_GTHREADS && _GLIBCXX_THREAD_ABI_COMPAT
unsigned int
thread::hardware_concurrency() noexcept
@@ -180,14 +192,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __n;
}
-_GLIBCXX_END_NAMESPACE_VERSION
-} // namespace std
-
-#endif // _GLIBCXX_HAS_GTHREADS
-
-namespace std _GLIBCXX_VISIBILITY(default)
-{
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace this_thread
{
void
